Lathe dog



A. M. FRASER.

LATHE DOG. APPLICATION FILED MN. 24, I920.

Patented June 13, 1922.

' provision being made for quickly and easily UNITED srAras PATENT: orrics.

ARTHUR M; FRASER, or wns'rBoB-o, MASSACHUSETTS. v

LATHE DOG.

To all whom it may concern:-

Be it known that I, ARTH R M. FRASER,

a citizen of the United States, residing at Westboro, in the countyof Worcester and State of Massachusetts, have invented new and useful Improvements in Lathe Dogs, of which thefollowing'is a specification.

i This invention relates to an improvement in lathe-dogs'and has for its object to provide a deviceforholding work in a lathe,

adjusting the device for different sizes of workfwithout necessitating the employment of tools ofany description.

- Another object of the invention 18 to entirely eliminate the use of screws either for adjusting the device-to fit the work or for clamping the work within the device.

' with faces each other face 6 of said jaw member. I the jaw 5 isprovidedw'ith a V-shaped notch The invention consists in the combination and arrangement of'parts set forth 1n the following v specification and particularly "pointed out in the claims thereof.

Referring to the drawings:

Figure 1 represents a front elevatlon of a, 1 th d embodying my" invention, the

work being shown clamped therein.

Fig. 2 is a side elevation f the same; Fig. 3 is a vertical section taken on the line 3-3'of Fig. 2.

Fig. 4 is a detail vertical section taken on the line 4-4 of Fig. 1.

Like numerals refer to like parts throughoutthe several views of the drawings. a In the drawings, 4 and 5 represent oppositely disposed jaw members provided 6 and 7 respectlvely ad acent to inserted. The jaw members 4 and 5 are con nected together by means of a pair of parallelly disposed toothed guide rods 9, thesaid rods being securely fastened to the jaw memher 4 ro'ectin erpendicularly from the 1 g p The face 7 of forced and 10 into wlnch the work 8 is rigidly held" by a clamp lever 11. The clamp lever 1-1=is located 1n a space 12 formed between two parallel walls 13 and is pivotally mounted upon a pin 14 which is supported in each of said walls 13.

The inner end of the clamp lever 11 con stitutes a cam 15, the periphery of which is eccentric relatively to the pin 14, The cam between which work 8 may be Patented June 13, 1922.

I 15 projects through an opening 16 provided in the face 6 of'the jaw 4 and engages the peripheryo-f the work 8. A spring 17 one end of which is secured to the jaw 5 and the other end to the lever 11, always acts to rock the lever 11 to bring the cam 15 into engagement with the work 8 thereby forcing said work into the V-shaped notch 10 of the jaw 5 and thereby firmly securing the work within the dog.

The outer end of the lever 11-is provided with a lateral projection 18 adapted to engage a slot provided in the face plate of a lathe," or if used in connection with a grinder a suitable projection 18 attached to a revolving portion of said grinder is adapted to engage the lever 11 as illustrated in dotted lines Fig. 1 and the dog together with the work held therein are rotated thereby in a manner well known to those skilled in the art. i

The jaw 5 is adjustably mountedupon the rods 9 to slide toward or away from the jaw 4 in order that work of difierent diameters may be clamped therebetween and, furthermore, after the aw 5 has been located .in its correct position it is automatically locked to the rods 9 in such a manner as to prevent the jaws 4 and 5 from separating complished in the following manner:

Mounted in grooves 19 provided in the jaw 5 are looking slides 20. The locking slides 20 have teeth 21 formed thereon which are adapted to engage corresponding teeth 22 provided upon the rods 9. The rods 9 project through slots 23 formed in the locking slides 20. Springs 24 act to alwa s force the teeth 21 of the locking slide -20 1nto engagement with'the teeth 22 of the rods 9 and when the teeth are thus engaged the jaw 5 is locked against movement away from the jaw 4 and cannot be moved upon the rods 9 to increase the distance between said jaws. The locking slides 20 are prevented from being forced out of the grooves 19 by their respective springs 24 when the jaw 5' is removed from the rods 9 by the presence of pins 25 which project from the opposite sides of the jaw 5 in front of projections 26 formed integral with the locking slides 20. The projections .26 furthermore prevent lateral displacement of the locking slides 20 within the jaws 10. The locking slides project beyond the ends of the jaw 5 a suflicient distance at 27 to be engaged by the fingers in order that said locking slides may be forced inwardly to release the teeth 21 of the locking slides from engagement with the teeth 22 of the rods 9.

The operation of my improved lathe-dog is as follows: If the diameter of the work requires increasing or diminishing the dis tance between the jaws 4L and 5, the outer ends 27 of the locking slides 20 are engaged by the fingers and said slides are forced inwardly simultaneously against the pressure of the springs until the teeth 21 of the locking slides become disengaged from the teeth 22 of the rods 9. The aw 5 may then slide in either direction upon the rods 9 until the j aws are correctly spaced, whereupon the locking slides may be released and the teeth 21 of said slides will again engage the teeth 22 of the rods 9. The jaw 5 may also be moved toward the jaw 4 upon the rods 9 by applying pressure to simultaneously force said jaws toward each other and causing the teeth 21 and 22 to slide upon each other, thereby forcing the locking slides inwardly. When operated in this manner the action is similar to a pawl and ratchet mechanism, the teeth 21 of the locking slides successively engaging the teeth 22 of the rods 9 as the jaws 4 and 5 approach each other and automatically locking the 5 to the rods 9 to prevent the separation of said jaws. While the dog is being applied and adjusted to the work 8 the outer end of the clamp lever 11 is held in its extreme position toward the right against the pressure of the spring 17.

en the jaws of the dog are finally adjusted the lever 11 is released and the spring 17 will rock the lever together with the eccentric cam 15 until said cam engages the work, whereupon the said work will be securely fastened within the dog. The work may then be inserted within a lathe and rotated in the usual manner.

Having thus described my invention what I claim and desire by Letters Patent to secure is:

1. A lathe-dog having, in combination, a jaw, a plurality of parallel rods fast to said jaw, teeth formed upon said rods, a second jaw slidably mounted'upon said rods and provided with grooves extending inwardly from each end thereof, and a plurality of locking slides mounted within said grooves and projecting outwardly therefrom at the outer end thereof, said locking slides being provided with teeth formed integral therewith adapted to yieldingly engage the teeth of said rods and prevent the separation of said jaws, said rods projecting through openings provided in said locking slides.

24A lathe-dog having, in combination, a

jaw, a plurality of parallel rods fast to said jaw, teeth formed upon said rods, a second jaw slidably mounted upon said rods, a plurality of locking slides, each provided with an opening formed therein, teeth formed through which said rods project integral with said locking slides and located within said opening at one side thereof, and springs to force the teeth of said locking slides into engagement with the teeth of said rods.

3. A lathe -dog having, in combination, a jaw, a plurality of parallel rods fast to said jaw, teeth formed upon said rods, a'second jaw slidably mounted upon said rods, a plurality of locking slides, through which sai d rods project, teeth formed on said locking slides, springs to force the teeth of said locking slides into'engagement with the teeth of said rods, the outer extremity ofsaid lockingslides constituting a means whereby the teeth of said locking slides may be forced out of engagement with the teeth of said rods, and means to clamp work between said aws. I

4. A lathe-dog having, in combination, a jaw, a pair of parallel rods fast to said jaw, teeth formed upon said rods, a second jaw slidably mount-ed upon said rods, a pair of locking slides through which said rods project, teeth formed on said locking slides, springs to force the teeth of, said locking slides into engagement with the teeth of said rods, a cam, and a coil spring adapted to rotate said cam into engagement with work located between said jaws and thereby clamp said work.

5. A lathe-dog having, in combination, a jaw, a pair of parallel rods fast to said jaw, teeth formed upon said rods, a second jaw slidably mounted upon said rods, a pair of locking slides mounted upon said slidable jaw through which said rods project, teeth formed upon said locking slides, springs to force said locking slides into engagement with the teeth of said rods, and pins to limit the movement of said locking slides upon said slidable jaw when said jaw is not in engagement with said rods, the outer extremity of each locking slide projecting beyond the outer extremity of said slidable jaw and constituting a means whereby said locking slides may be forcedinwardly and the teeth thereof disengaged from the teeth of said rods;

6. A lathe-dog having, in combination, a jaw, a pair of parallel rods fast to said jaw,

teeth formed upon said rods, a second jawslidably mounted upon said rods, a pair of locking slides mounted upon said slidable jaw and projecting beyond the extremities thereof, teeth formed upon said locking slides, means to force said locking slides intoengagement with the teeth of said rods, said locking slides embodying therein means contacting with the opposite outer surfaces of said slidable jaw adapted. to prevent my hand in presence of two subscribing witlateral movement of saidlocking slides upon nesses.

said slidable jaw and means to limit the out- Ward movement of said locking slides upon ARTHUR FRASER 5 said slidable jaw when said jaw is not in en- Witnesses:

gagement with said rods. P. J. HAWKEY,

In testimony whereof I have hereunto set CARL S. PRINGLE. 

